Fix known typos

Sweep the codebase for common typos. Includes some changes to visible function
names that were misspelt.

llvm-svn: 200018
diff --git a/llvm/unittests/Support/FileOutputBufferTest.cpp b/llvm/unittests/Support/FileOutputBufferTest.cpp
index b81bdb5..6d62999 100644
--- a/llvm/unittests/Support/FileOutputBufferTest.cpp
+++ b/llvm/unittests/Support/FileOutputBufferTest.cpp
@@ -68,7 +68,7 @@
     memcpy(Buffer2->getBufferStart(), "AABBCCDDEEFFGGHHIIJJ", 20);
     // Do *not* commit buffer.
   }
-  // Verify file does not exist (because buffer not commited).
+  // Verify file does not exist (because buffer not committed).
   bool Exists = false;
   ASSERT_NO_ERROR(fs::exists(Twine(File2), Exists));
   EXPECT_FALSE(Exists);